Silicone oil has good properties such as refreshed feel, smooth spreading and good water repellency, and therefore it has been widely used as an oil agent for cosmetics. In particular, low-viscosity silicone oil provides a cosmetic which has non-tackiness and light feel, and therefore it has been much used.
The silicone oil lacks in compatibility with general oil agents and thickening agents, and therefore, it is difficult to control a viscosity of the low-viscosity silicone oil. Oil agents such as silicone oil are made pasty with a specific silicone gel and have been commercially available as a material for adjusting membrane feel. For example, KSG-15, KSG-16 and KSG-045Z are commercially available from Shin-Etsu Chemical Co., Ltd. These materials have been widely used in various kinds of cosmetic because they can control a viscosity of cosmetics and provide a special continuous membrane feel which is not obtained from a powder material.
However, if these materials are added to cosmetics in a large amount to attain sufficient membrane feel of cosmetics, they are liable to give a somewhat tackiness to a skin treated with the cosmetics. Therefore, there is a need for a material which has lower tackiness. Japanese Patent Publication No. Hei-6-55897, Japanese Patent Publication No. Hei-8-6035, Japanese Patent No. 2582275 and Japanese Patent No. 3242874 disclose methods where a silicone polymer and low-viscosity silicone oil are processed with by a shearing force in the presence of a specific silicone gel as a thickening agent for the low-viscosity silicone oil to provide a uniform pasty composition. However, if an amount of the silicone gel added is large, the cosmetic is liable to give tackiness to a skin. According to the research in respect to a production method of a thickening agent for silicone and the thickening effect described in J. Soc. Cosmet. Chem. Jpn., 27 (3), 480-483 (1993), it is known that the presence of a silicon oil which is unreactive with a silicone polymer in the production process of the silicone polymer significantly increases the thickening effect in proportion to the amount of the silicone oil added. However, if the amount of the silicone oil added is increased, the tackiness increases also on the skin which the silicon polymer obtained is applied to.
A silicone polymer which has a side chain in a part of the crosslinking structure is suggested for improving the tackiness in Japanese Patent Application Laid-Open No. 2008-115358, but the improvement is insufficient. Further, a cosmetic with such a silicone polymer shows significantly poor oil repellency, its membrane strength is reduced by a sebum, and a function for preventing color migration is insufficient. Further, its rub resistance is insufficient. Japanese Patent Application Laid-Open No. 2000-327528 describes a method where a fluorine-containing compound, in particular a high molecular weight compound having a molecular weight of 5,000 to 1,000,000 is added to a cosmetic together with the aforesaid pasty silicone composition. However, this fluorine-containing compound with a high molecular weight have very low affinity with other materials and, therefore, is liable to separate in a cosmetic with time, increases the viscosity of the cosmetic. Accordingly, its amount and selection of the other materials are restricted.
Japanese Patent No. 4341871 describes a uniform pasty composition which has swellability with fluorine-modified silicone oils having a high content of fluorine-substituted alkyl groups, such as penta-3,3,3-trifluoropropyl pentamethyl cyclopentasiloxane, and has good water- and oil-repellency. This composition gives refreshed feel to a cosmetic, but has poor affinity with silicone materials without a fluorine-substituted alkyl group and other cosmetic low materials, and its stability is bad with time. Accordingly, its amount and selection of the other materials are restricted.